1. Field of the Invention
The present invention relates to a display, wiring board, and method of manufacturing the same.
2. Description of the Related Art
In a display such as a liquid crystal display or organic EL (Electroluminescent) display, wiring line groups of flexible tapes are connected to OLB (Outer Lead Bonding) pad groups formed on a display panel to make it possible to supply a power or signal from the outside of the display panel to circuits in the panel. For example, in a display on which a control driver is COG (Chip On Glass)-mounted, wiring lines are laid out on a glass substrate such that wiring line groups which connect video signal line groups (or video signal line driver) or scan signal driver to OLB pad groups arranged on one side of the glass substrate are formed. Accordingly, all electrical connections between the interior and exterior of the display panel can be realized on one side of the rectangular display panel.
In manufacturing the above-described display, pixel circuits in the display region or OLB pad groups and wiring line groups in the peripheral region are formed by using a photolithography process. A substrate used in a display is much larger than that used in a semiconductor device. For this reason, in manufacturing a display, it is difficult to execute full plate exposure for the entire display region and peripheral region. Hence, the display region or peripheral region is segmented into a plurality of parts, and exposure is sequentially executed for the parts.
More specifically, a plurality of patterns are formed on one reticle. Exposure with one pattern is repeated. Next, exposure with another pattern is repeated. When exposure of all the patterns formed on the reticle is ended, the reticle is exchanged. Still other patterns sequentially undergo exposure.
As described above, in the display manufacturing process, a complex exposure step is necessary, and the exposure step requires long time. Switching between patterns formed on the same reticle takes not so long time as reticle exchange. To shorten the time required for the exposure step, all patterns may be formed on one reticle. In this case, however, the size of each pattern must be reduced. As a result, since the number of times of exposure (the number of shots) increases, the time required for the exposure step cannot be shortened.
Jpn. Pat. Appln. KOKAI Publication No. 2000-112383 discloses a prior art related to the present invention.
This reference is related to a display on which a plurality of driver ICs are COG-mounted. To decrease the number of pads on the flexible tape or the number of pads on the panel, the input terminals of the driver ICs are appropriately distributed to two end portions of the array direction of the driver ICs. More specifically, one pad can input a signal to two adjacent driver ICs.
However, this reference includes no description about the above-described problem in the exposure step. In this reference, only the structure of the intermediate portion of the array, which the driver ICs form, is described, and the structure of the end portions of the array is not described. Additionally, in the structure described in this reference, each of wiring lines running in the array direction of the driver ICs is connected to a power supply or signal source.